To Cite or Not to Cite?

Over at Concurring Opinions, Dan Solove asks the not-so-musical question, "when is it appropriate to cite to Wikipedia?" Although I know some people have a problem with Wikipedia, it seems to be fairly accurate, at least for non-controversial topics. I wouldn't cite it for a massively critical piece of evidence in an argument before a court. But, sometimes, you just need a cite for something tangentially relevant but not super important. I don't think I've ever used Wikipedia in a brief, but I cited Mapquest directions before to show the distance between two addresses that, while commonly known to the parties and trial court before which the issues was first argued, surely weren't know to the judges in Richmond. If the mileage was off a little bit, it wasn't really important - it was just providing some context. Similarly, I can see good uses for an occasional Wikipedia cite used in similar fashion.

UPDATE: The comment by Christine Hurt over at Concurring Opinions brings up a valid point - we in the legal world are addicted to citations (I can usually cull half the length of a law review article in WestLaw form just by not printing out the endnotes). As long as we are, Wikipedia can be a good source of "common" knowledge.